Depilatory method and means

ABSTRACT

A method by which to accelerate electrolytic destruction of hair. The method involves application to the hair papilla associated with the hair, of current having a unidirectional current component and a radio frequency current component. The unidirectional current produces ions which kill electrochemically. The radio frequency current accomplishes heating less than enough to result in radio frequency burning of the papilla but enough to accelerate the electrochemical processes. An apparatus furnishes unidirectional currents modulated at a radio frequency rate through an impedance changing circuit which constitutes a constant voltage source to the radio frequency generator and which constitutes a high impedance, constant current source to the body thereby to offer protection both to the subject and to the radio frequency generator.

United States Patent [19] Sramek DEPILATORY METHOD AND MEANS Inventor:Bohumir Sramek, 19211 Edgehill Dr., Irvine, Calif. 92664 Filed: Oct. 16,1972 Appl. No.: 298,178

US. Cl. l28/303.l8, 128/421 Int. Cl. A6lb 17/40, A61n 3/04 Field ofSearch -128/303.l8, 419 R, 421

[56] References Cited UNITED STATES PATENTS 6/1948 St. Pierre l28/303.18X

9/1962 Tapper l28/303.l8 3,160,159 12/1964 Howdy et al 128/1 C X3,255,753 6/1966 Wing 128/421 FOREIGN PATENTS OR APPLICATIONS 897,9616/1962 Great Britain 128/303.14

OTHER PUBLICATIONS [4 June 11, 1974 Primary Examiner-Channing L. PaceAttorney, Agent, or FirmGrover A. Frater [5 7 1 ABSTRACT A method bywhich to accelerate electrolytic destruction of hair. The methodinvolves application to the hair papilla associated with the hair, ofcurrent having a unidirectional current component and a radio frequencycurrent component. The unidirectional current produces ions which killelectrochemically. The radio frequency current accomplishes heating lessthan enough to result in radio frequency burning of the papilla butenough to accelerate the electrochemical processes. An apparatusfurnishes unidirectional currents modulated at a radio frequency ratethrough an impedance changing circuit which constitutes a constantvoltage source to the radio frequency generator and which constitutes ahigh impedance, constant current source to the body thereby to offerprotection both to the subject and to the radio frequency generator.

12 Claims, 2 Drawing Figures DEPILATORY METHOD AND MEANS This inventionrelates to an improved method of depilation and to improved depilatoryapparatus.

Permanent removal of hair can be accomplished by destroying the papillaassociated with the hair root. Destruction of the papilla can beaccomplished chemically and the conditions for that chemical destructioncan be established by dissociating water into hydrogen cations andhydroxile anions in the immediate vicinity of the papilla. Thedissociation is accomplished by causing electric currents to flowthrough body liquid which is primarily water. To insure a highconcentration of charge, electrolytic depilatory apparatus customarilyemploys a wet pad as a positive electrode through which electricalcontact is made to the body-water in the region of the hair to bedestroyed but spaced from that hair. A fine wire probe is used as anegative electrode. It is inserted into the hair follicle to a pointnear the papilla associated with the root of the hair to be destroyed.The chemical killing action is proportional to the degree of waterdissociation.- The quantity of chemical action available for destroyingthe papilla is related directly to the number of ions that flow. If flowrate or current is low, then a longer time is required. If the time isto be shortened then current must be increased. However, the chemicalaction that results in destruction of papilla effects the nervous systemto produce pain. It is approximately true that painfulness of theprocess increases in proportion to the effectiveness in destroying hair.

The papilla can also be destroyed by heating. While that process is notentirely understood, it is well-known that high frequency alternatingcurrents can destroy cells, including those in the papilla. A radiofrequency burn results. When such currents flow from the end of a needleinserted in a body of tissue, cells in the immediate vicinity of thepoint where current leaves that needle are burned in the way that theywould be burned by the application of heat.

Both electrolysis and radio frequency heating have been employed inremoving hair. Both are effective and both are painful. Some degree ofsuccessin reducing the pain appears to have been achieved by using thoseprocesses on an alternating basis'so that unidirectional current isapplied to the papilla for a succession of short periods and pulses ofradio frequency currents are applied in the periods between them. Thatkind of alternation is said to make the whole process less painful.Another prior method involves omitting the electrolysis and relying onR. F. burning in a procedure that applies pulses of radio frequencycurrents such that amplitude and duration is increased in successivepulses. That approach is also said to be less painful. Another approachin the prior art was to combine electrolytic action with what appears tobe an attempt to place the papilla within a high frequencyelectromagnetic field. It is not clear what effect, if any, was producedby thefield.

In this invention, heating with radio frequency current is combinedwithelectrolytic action. However, the level of radio frequency heating ismaintained at a low value so that no radio frequency burning results.Instead, radio frequency heating is maintained at a lower level whereitseffect is to accelerate the chemical action between theions and the cellto be destroyed. An electrically conductive probe is inserted into thesubjects skin, advantageously through a hair follicle down to the regionof the papilla. A second electrode is placed over a nearby area of thesubjects skin. Current is then made to flow between those electrodes.That current has a unidirectional component and a high frequencyalternating component which are added according to the electrical law ofsuperposition. The resultant current is effective to produce papilladestruction with less current than would be required if the alternatingcurrents were not superimposed on the unidirectional current. Lessercurrent means less pain. More importantly, combining the alternating andunidirectional currents makes it possible to accomplish papilladestruction in shorter time than is required when unidirectional currentis used alone. That means that papilla destruction can be accomplishedwith shorter pain periods.

If the peak value of the alternating current exceeds the value of theunidirectional current then polarity will be changed for short periodsand current will be reversed for those short intervals. The preferredmethod is to superimpose alternating currents at radio frequencies upona unidirectional voltage such that the peak value of the alternatingcomponent is less than the DC value. Polarity is not changed when thatis done.

One way to supply such a compositevoltage is to generate a series ofunidirectional pulses at high frequency. Another is to rectify a radiofrequency signal. The method of the invention may employ any of theseapproaches and an apparatus for practicing those different approaches isshown in FIG. 1. However, a preferred apparatus for generating thevoltage, and for use in practicing the method of the invention, isillustrated in FIG. 2. The circuit and apparatus there shown has theadvantage that the unidirectional and radio frequency components may bealtered simultaneously without changing the ratio of DC to AC voltage.It is arranged so that'the subjects body sees a high impedance currentsource for increased safety. The apparatus has the added advantage thatit can be produced at low cost with a high order of reliability.

' An object of the invention is to provide an improved method forremoval of hair by destruction'of papilla by chemical means. It is anobject to accelerate the chemical action by localized heating. A relatedobject is to insure that the means for accelerating heating does notbecome an instrument for producing R. F. burning. Other objects are toprovide an apparatus which is simple to use, is safe and is reliable. Aprimary object, of course, is to provide an effective hair removal meansthat getsthe job done with little or no pain.

In the drawings:

FIG. 1 is a generalized schematic diagram of apparatus embodying theinvention; and

FIG. 2 is a circuit diagram of a'preferred embodiment of the invention.

In FIG. 1 the dash-line 10 represents a portion of the subjects body.The resistor 12 represents the impedance presented by that portion ofthe body to the flow of electric current. The impedance is primarilyresistive. The symbol 14 represents a hair follicle which probe 16enters to make electrical contact with the body in the region of thepapilla associated with the root of the hair that extends from folliclel4 and which it is the purpose of the apparatus to destroy. A shortdistance away from that follicle a wet pad 18 is applied to the subjectsbody. Moisture in the pad joins with the moisture at the surface in thesubjects skin to complete an electrical circuit from the probe 16 to thepad 18. The probe and the pad and the manner in which they areassociated with the body are old and well-known. But the manner heretaught of energizing that circuit with unidirectional and radiofrequency currents is novel. The generalized circuit arrangements areshown in FIG. 1. Pad 18 is connected by line 20 through an ad justablecurrent limiter 21 to one side of a radio frequency alternating voltagegenerator 22. The output of the generator isapplied by line 24 to asingle pole double throw switch 26 which, if thrown to pole 28,completes a circuit from the generator through conductor 7 30 and aunidirectional voltage source 32 to line 34 which connects to the probe16. Thus connected a current is caused to flow through the patients bodywhich is described as a unidirectional current on which an alternatingcurrent is superimposed.

If the movable contact of switch 26 is thrown instead to pole 36 then acircuit will have been completed from pad 18 through line 20,alternating radio frequency generator 22, line 24, switch 26, rectifier38, and conductor 34 to probe 16. By that circuit a half waverectifiedcurrent in the form of pulses at radio frequency flows throughthe circuit. The resulting wave has both a DC and an AC component and isnot unlike the current that flows through the subject when, in the otherswitch position, the alternating radio frequency generator 22 andthebattery 32 are connected in series. In the preferred method of theinvention the peak value of the alternating voltage is no greater thanthe battery voltage so that current flow is unidirectionalnotwithstanding its change in amplitude.

The circuit illustrated in FIG. 2 is capable of operation according tothat preferred method. In fact, it can only operate according to thepreferred method. Several important advantages are attained by thiscircuit. First it uses few components all of which are relativelyinexpensive whereby cost is'minimized. Reliability is enhanced becausethere are fewer parts and fewer connections to fail. It will be apparentfrom the description of the circuit that transistor 9 serves as aconstant current source for the body and a constant voltage source forthe oscillator. Its high output impedance serves to protect .the bodyagainst excessive current flow whereas its low input impedance helps toinsure a constant voltage supply to the oscillator and stability in itsoperation.

Safety is also enhanced by the fact that the body, the constant currentsource 9, the crystal controlled oscillator 47, the current adjuster R2and the foot switch 44 are all in series so that the system tends to befail safe in the event of a failure to produce an open circuit. Thatcircuit arrangement makes it possible to turn the current off while theprobe is being inserted into the follicle, to turn the current on onlyafter the probe has been inserted, and to turn it off before the probeis withdrawn. Permitting the flow only while the probe is fully insertedis advantageous for several reasons. Having the current turned on whilethe probe is being inserted or withdrawn results in scarring and mayresult in pain at a time when no useful purpose is being served bycurrent flow.

Stability is promoted in this circuit by the use of a properlyterminated coaxial cable 42 which is used to transfer the direct currentand the radio frequency current components to the probe withoutreflection and without radiation. That is made possible by the use oftransistor 9 and resistor R4.

In FIG. 2 the numeral 10 represents the subject's body. The resistor 12,as in the case of FIG. 1, represents the impedance offered by the bodyto flow of current from the probe 16 to the wet pad 18. Power for theunit is supplied by battery 40 whose positive terminal is connected tothe shield of coaxial cable 42 and the wet pad 18 and whose negativeterminal is connected through a normally open foot switch 44 to line 46at one side of crystal oscillator 48. That crystal oscillator isconnected between lines 46 and a line 48 which includes in series theresistor R1 and a rheostat R2. The other side of the rheostat isconnected through a milliammeter 50 to the center conductor of thecoaxial cable 42. A bypass capacitor 52 is connected across themilliammeter to bypass the radio frequency component of the currentwhereby average current values are shown.

The crystal oscillator 47 comprises an NPN transistor 54 whose emitteris connected to line 46. The collector is connected to line 49. The baseof the transistor is connected by a line 56 to a resistor R3 whose otherend is. connected to line 49. A piezoelectric crystal 58 is connected inparallel with that resistor from the base to the collector of thetransistor. The base and emitter are connected through a capacitor 60.Another capacitor 62 is connected between the emitter and the collector.

of the transistor 54. Together the two capacitors 60 and 62 form a highfrequency voltage divider for controlling the amount of feedback signalapplied to the crystal and to the base-emitter junction. The crystalcontrolled oscillator is effective to generate unidirectional signalsvarying in amplitude at radio frequencies and more particularly at13.560 MHz which has-been as signed by the Federal CommunicationsCommission for such purposes. The current through the oscillator doesnot alternate; it undulates without changing direction. The peakamplitude of the alternating component is almost equal to theunidirectional component.

At its output the center conductor of the coaxial cable is connectedthrough a resistor R4 to the emitter of NPN transistor 9. The shield ofthe coaxial cable is connected to a line 70. Tha line connects to thewet pad 18. The base of transistor 9 is connected to that line 70through a Zener diode 72. Finally, the circuit is completed byconnection from probe 16 through line 74 to the collector of transistor9.

The battery 40 supplies 27 volts to the circuit. The Zener diode 72 is a22 volt unit. Tracing the DC circuit, the positive terminal of thebattery is connected to the outer conductor of shield 42 by conductor76. Line 70 connects the shield to one side of the 22 volt Zener diodewhich is polarized so that the base of the transistor is maintained at apotential of 22 volts. The emitter base junction of transistor 9 isapproximately 0.8 volts so that the potential of the emitter is'anegative 22.8 volts. That arrangement of battery 40, Zener diode 72 andthe base-emitter junction of transistor 9 serves as a constant voltagesource for the application of 4.2 volts to the network consisting of thecrystal 'oscillator, the milliammeter 50, and the current controlresistors R1 and R2 and coaxial cable terminating resistor R4. R4combines with the impedance of the baseemitter junction of transistor 9and the impedance across the Zener diode 72'to provide a matchingtermination for the coaxial cable 42. In practice, R4 has a value of 35ohms in a circuit using a 50 ohm coaxial cable.

The voltage drops across the Zener diode and the emitter base junctionof transistor 9 are constant as is the voltage across the battery.Therefore, the average current flow in the generator circuit is affectedsubstantially only by the value of adjustable resistor R2. Thus, thecurrent flowing through transistor 9 and the subject is affected only bythe adjustment of R2. The resistance of the subject may vary greatlyfrom time to time and from place to place on the subjects body dependingprimarily upon the degree of perspiration and the character of the fleshthrough which current flows. The body resistance 12 is usually aboutthousand ohms but may vary from 1 to thousand phms. The circuitarrangement maintains substantially uniform current through the subjectdespite those changes. That means that the voltage across the subjectvaries over a ratio of about 20:1. That voltage is in series with, andhas polarity opposite to, the 22 volts across the Zener diode. As longas the voltage across the subject is less than 22 volts the collector isproperly biased. The collector current is relatively independent ofbase-collector bias; the combination of Zener diode and transistor 9constitutes a high impedance source to the subjects resistance 12.

This feature is important. It means that a milliammeter connected in thecircuit at a distance from the probe is a dependable indicator of thequality of current to which the patient is subjected. Since the radiofrequency component cant exceed the unidirectional component, only a DCmeter is required. Such a meter is also an accurate indicator of radiofrequency component because the two components always have the samerelative value. Control is easy because current remains essentially thesame notwithstanding changes in internal resistance of the subject andchanges in contact resistance between the body and the wet padelectrode.

Although I have shown and described certain specific embodiments of myinvention, I am fully aware that many modifications thereof arepossible. My invention, therefore, is not to be restricted exceptinsofar as is necessitated by the following claims.

I claim:

l. The method of removing hair from a subject by chemical destruction ofthe papilla associated with the hair root which comprises the steps of:

placing a first electrode in the immediate vicinity of the papilla and asecond electrode in direct electrically conductive contact with thesubject at a point removed from the hair and its papilla;

causing electric currents to flow through the subject by applying acrosssaid first and second electrodes a high frequency alternating voltagesuper-imposed on a unidirectional voltage.

2. In an electrical depilatory apparatus of the kind in which electricpotential is impressed across electrodes to be applied to a subject, onein the vicinity of a papilla to be destroyed and theother nearby, theimprovement which comprises:

a first electrode means in the form of a metallic stylet for conductingelectric currents below the surface of the skin of a subject in thevicinity of a papilla;

a second electrode means in the form of an electrically conductive padcapable of overlying an area of a subjects skin for conducting currentsbetween said pad and said area; and

potential application means for applying across said first and secondelectrodes a potential having a unidirectional component and analternating component at radio frequency.

3. The invention defined in claim 2, said potential application meanscomprising the series circuit combination of a unidirectional voltagesource, a radio frequency undulating voltage source and a variable resistor whereby adjustment of the resistor controls the flow of bothunidirectional and alternating components of current flowsimultaneously.

4. The invention defined in claim 3 in which said potential applicationmeans further comprises an active element of the kind having a primaryflowpath and a control electrode, the primary flowpath being connectedin series in said series circuit combination; and means for impressingsaid alternating voltage and at least a portion of said unidirectionalpotential on said control electrode.

5. The invention defined in claim 2 in which said potential applicationmeans comprises: a transistor having its base to collectorjunctionconnected across said electrodes; a fixed voltage means fordeveloping a fixed voltage drop connected in series between the base ofsaid transistor and one electrode; the series circuit combination of aunidirectional voltage source, greater than said fixed voltage drop; anda radio frequency voltage generator connected from said one electrode tothe emitter of said transistor.

6. The invention defined in claim 5 in which said series circuitcombination further comprises a variable series resistor and a seriesoperating switch.

7. The invention defined in claim 6 in which said fixed voltage sourcemeans comprises a Zener diode.

8. The invention defined in claim 6 in which said series circuit furthercomprises a length of coaxial cable the center conductor of which isconnected to the emitter of said transistor and the outer conductor ofwhich is connected to said one electrode.

9. The invention defined in claim 8 in which said series circuit furthercomprises a current meter.

10. The invention defined in claim 8 in which said radio frequencyvoltage generator comprises a crystal oscillator of the kind thatpermits flow of undulating unidirectional current whose alternatingcomponent has peak value no greater than its unidirectional component.

11. The invention defined in claim 10 in which the crystal oscillatorcomprises an oscillator transistor having its collector and emitterconnected in series in said series circuit combination, a piezoelectriccrystal connected between the base of the oscillator transistor and oneof its collector and emitter elements, and a first ca pacitor connectedfrom the base of the oscillator transistor to the other of its collectorand emitter elements, and a second capacitor connected from thecollector of the oscillator transistor to its emitter.

12. In combination:

a pad electrode;

a Zener diode;

a length of coaxial cable having its outer conductor connected to saidpad electrode and to one side of said diode;

a radio frequency generator comprising an NPN oscillator transistor, afirst capacitor connected from a switch and a variable resistor inseries with said source of unidirectional potential and said oscillatortransistor between said inner and outer conductors of said cable;

a probe electrode; and

an impedance transforming NPN transistor having its collector connectedto said probe electrode, having its base connected to the other side ofsaid Zener diode, and having its emitter connected to the centerconductor of said coaxial cable.

1. The method of removing hair from a subject by chemical destruction ofthe papilla associated with the hair root which comprises the steps of:placing a first electrode in the immediate vicinity of the papilla and asecond electrode in direct electrically conductive contact with thesubject at a point removed from the hair and its papilla; causingelectric currents to flow through the subject by applying across saidfirst and second electrodes a high frequency alternating voltagesuper-imposed on a unidirectional voltage.
 2. In an electricaldepilatory apparatus of the kind in which electric potential isimpressed across electrodes to be applied to a subject, one in thevicinity of a papilla to be destroyed and the other nearby, theimprovement which comprises: a first electrode means in the form of ametallic stylet for conducting electric currents below the surface ofthe skin of a subject in the vicinity of a papilla; a second electrodemeans in the form of an electrically conductive pad capable of overlyingan area of a subject''s skin for conducting currents between said padand said area; and potential application means for applying across saidfirst and second electrodes a potential having a unidirectionalcomponent and an alternating component at radio frequency.
 3. Theinvention defined in claim 2, said potential application meanscomprising the series circuit combination of a unidirectional voltagesource, a radio frequency undulating voltage source and a variableresistor whereby adjustment of the resistor controls the flow of bothunidirectional and alternating components of current flowsimultaneously.
 4. The invention defined in claim 3 in which saidpotential application means further comprises an active element of thekind having a primary flowpath and a control electrode, the primaryflowpath beiNg connected in series in said series circuit combination;and means for impressing said alternating voltage and at least a portionof said unidirectional potential on said control electrode.
 5. Theinvention defined in claim 2 in which said potential application meanscomprises: a transistor having its base to collector junction connectedacross said electrodes; a fixed voltage means for developing a fixedvoltage drop connected in series between the base of said transistor andone electrode; the series circuit combination of a unidirectionalvoltage source, greater than said fixed voltage drop; and a radiofrequency voltage generator connected from said one electrode to theemitter of said transistor.
 6. The invention defined in claim 5 in whichsaid series circuit combination further comprises a variable seriesresistor and a series operating switch.
 7. The invention defined inclaim 6 in which said fixed voltage source means comprises a Zenerdiode.
 8. The invention defined in claim 6 in which said series circuitfurther comprises a length of coaxial cable the center conductor ofwhich is connected to the emitter of said transistor and the outerconductor of which is connected to said one electrode.
 9. The inventiondefined in claim 8 in which said series circuit further comprises acurrent meter.
 10. The invention defined in claim 8 in which said radiofrequency voltage generator comprises a crystal oscillator of the kindthat permits flow of undulating unidirectional current whose alternatingcomponent has peak value no greater than its unidirectional component.11. The invention defined in claim 10 in which the crystal oscillatorcomprises an oscillator transistor having its collector and emitterconnected in series in said series circuit combination, a piezoelectriccrystal connected between the base of the oscillator transistor and oneof its collector and emitter elements, and a first capacitor connectedfrom the base of the oscillator transistor to the other of its collectorand emitter elements, and a second capacitor connected from thecollector of the oscillator transistor to its emitter.
 12. Incombination: a pad electrode; a Zener diode; a length of coaxial cablehaving its outer conductor connected to said pad electrode and to oneside of said diode; a radio frequency generator comprising an NPNoscillator transistor, a first capacitor connected from the emitter tothe collector of the oscillator transistor, a second capacitor connectedfrom the emitter to the base of the oscillator transistor, apiezoelectric crystal connected from the base to the collector of theoscillator transistor, and a first resistor shunting said crystal; asource of unidirectional potential connected in series with said radiofrequency generator between the outer and inner conductors of thecoaxial cable such that the positive side of the source and the emitterof the oscillator transistor are toward the outer conductor of thecable; a switch and a variable resistor in series with said source ofunidirectional potential and said oscillator transistor between saidinner and outer conductors of said cable; a probe electrode; and animpedance transforming NPN transistor having its collector connected tosaid probe electrode, having its base connected to the other side ofsaid Zener diode, and having its emitter connected to the centerconductor of said coaxial cable.